When a computer device encounters a power failure suddenly, to prevent data loss in a memory, a power backup function needs to be enabled to write data in the memory to a hard disk.
Generally, data stored in a memory includes dirty data and common data. The dirty data is data that is newly written or data that is modified. The common data is data that is read from a hard disk and that is not modified. When data backup is performed, generally, only the dirty data needs to be backed up. However, because the dirty data is randomly written to different locations in the memory when data is written, power needs to be globally supplied to the memory after the computer device encounters a fault or a power failure, until the data in the memory is completely written to the hard disk.
However, the memory is an element that consumes a relatively large amount of power, and therefore consumes a relatively large amount of electric energy of a backup power supply.
In addition, during normal operation, the computer device may perform only one operation such as a read operation or a write operation for a long period of time. However, even if only a single operation is performed, the entire memory needs to be in a normal power supply state, and therefore consumes a relatively large amount of power.